Of course they would say that, but it is at odds with the
letter signed by numerous technical engineers, which states quite clearly they didn't undergo a proper independently verified prototype testing program as advised by regulatory bodies. That is by definition cutting corners.
No element of a novel or experimental vehicle can be considered safe until it has been through a rigorous testing program, because until that is done, its safety and efficacy is entirely theoretical.
They can state that they built something which they felt in good faith was sufficient for the depth required. The fact is, they never proved it and that is almost certainly why it is now lying 6,000m deep in the ocean.